Ignore my previous note, I forgot to add in where to use the PECL command to install phplua.
Installation on Ubuntu 14.04
"*.*" means version number
Packages to install (sudo apt-get install):
Create soft link of /usr/include/lua TO /usr/include/lua*.*:
sudo ln -s /usr/include/lua*.*/ /usr/include/lua
Find liblua*.*.so and liblua*.*.a files in /usr/lib.
If they don't exist, they could be in /usr/lib/x86_64-linux-gnu or /usr/lib/i386-linux-gnu depending on OS.
Copy them from that directory into /usr/lib as liblua.so and liblua.a (WITHOUT VERSION NUMBER).
sudo cp /usr/lib/x86_64-linux-gnu/liblua5.2.a /usr/lib/liblua.a
Now execute the following command (1.1.0 is the version at the time of writing this):
sudo pecl install lua-1.1.0
Add extension=lua.so to php.ini file (could be /etc/php5/(cli/apache)/php.ini)
Hope this helps.